This invention relates to electron-beam lithographic apparatus and, more particularly, to electron-beam lithographic apparatus for drawing fine patterns on such objects as semiconductor wafers and mask substrates.
Hitherto, various electron-beam lithographic apparatus have been used for the manufacture of IC devices. These electron-beam lithographic apparatus include a table carrying a silicon wafer which is moved in a regular raster scan pattern while an electron beam scans the silicon wafer in a direction perpendicular to the direction of travel of the table. In this apparatus, rectangular or trapezoidal patterns are converted into digital data consisting of "1"s and "0"s, and the digital data are transmitted as blanking data to a blanking device for on-off controlling the electron beam. However, with the prior art raster scan type electron lithographic apparatus, addresses in which line data corresponding to electron beam scanning lines are calculated from the coordinate data representing the coordinates of the apices of pattern, and a bit pattern is formed in pattern memories for the individual lines. When the bit pattern is formed in a pattern memory, it is read out bit by bit from the pattern memory and supplied to the blanking device. In this system, if the pattern to be drawn is complicated and of a high density, the process of converting the pattern coordinate data into address data is complicated and the time required for the process is increased.